Method and system for determining structural changes in a longwall mine

ABSTRACT

A system for determining structural changes in a longwall mine, including a modulator wheel operatively coupled to a longwall mining machine, and a controller in communication with the modulator wheel; wherein the controller determines a movement of the longwall mining machine according to a signal received from the modulator wheel.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and the benefit of Australian Patent Application No. 2012901236, filed on Mar. 27, 2012, the disclosure of which is incorporated herein in its entirety by reference.

FIELD OF THE INVENTION

This invention relates generally to a method and system for determining structural changes in a longwall mine, and in particular to a device for determining a position of a rock face of the longwall mine.

BACKGROUND TO THE INVENTION

A longwall mine is constructed by excavating two parallel tunnels, known as gate roads, leading into a material to be mined. A cross tunnel that connects the gate roads is then excavated in which a longwall mining machine is constructed. The length of the cross tunnel and hence the width of the longwall mining machine is typically between 150 m and 400 m.

The longwall mining machine includes cutters or shearers which cut the material, such as coal, from a rock face. The material falls onto an armoured face conveyor that travels along the width of the longwall mining machine to an end of the cross tunnel to one of the gate roads. The material is then conveyed onto a beam stage loader located in the gate road. Once on the beam stage loader the material then passes through a crusher which breaks down any large materials. The beam stage loader then conveys the material onto a conveyor belt which in turn conveys the material to the surface of the mine. Once the material has been cut, pneumatic ram roof supports are automatically positioned in place of the cut material. As the longwall mining machine retreats towards an entrance to the gate roads, the roof behind collapses in a planned and controlled manner.

Services for a longwall mining machine, such as power, communications, hydraulic fluid and water are supplied along flexible conduits and cables. The flexible conduits and cables are mounted to a monorail system which in turn is mounted to a ceiling of the gate road allowing the services to concertina as the mining machine retreats. A positioning system mounted to the monorail system determines a position of the rock face or longwall mining machine and transmits this positional information along a communications line to the surface in order that mine management may determine mining progress.

A prior art positioning system is disclosed in US patent publication number US 200910134692. The system includes a laser mounted to a carriage on the monorail. The laser scans forwardly into the gate road or backwardly along the gate road to determine the position of the longwall. However there are several problems with this system. First, the system is heavy and needs lifting equipment to be installed. Second, the system can be affected by electrical noise and magnetic fields. Third, as a mine environment is dusty, a lens of the laser needs to be cleaned frequently and a clear line of sight is needed for the measurement to work. Fourth, the system needs to be installed in a certified fireproof enclosure. Fifth, the fireproof enclosure requires periodic testing. Sixth, these systems require line of sight to perform the measurement which can be difficult in the confines of a mine. Finally, the measurement may be less accurate due to environmental conditions such as dust and moisture.

There is therefore a need for an improved system and method for determining structural changes in a longwall mine.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge in Australia or elsewhere.

SUMMARY OF THE INVENTION

In one form, although not necessarily the only or broadest form, the invention resides in a system for determining structural changes in a longwall mine, including:

a modulator wheel operatively coupled to a longwall mining machine; and

a controller in communication with the modulator wheel;

wherein the controller determines a movement of the longwall mining machine according to a signal received from the modulator wheel.

Preferably, the modulator wheel is an optical modulator wheel. Alternatively, the modulator wheel is an electrical modulator wheel.

Preferably, the controller is in optical communication with the modulator wheel. Alternatively, the controller is in electrical communication with the modulator wheel.

Preferably, the modulator wheel frictionally engages with a rail of a monorail system supplying services to the longwall mining machine.

Preferably, the modulator wheel is mounted to an arm.

Preferably, the arm is mounted to an end carriage of the monorail system.

Preferably, an optical fibre connects the controller to the modulator wheel.

Preferably, the controller is connected to a local area network.

In another form, the invention resides in a system for determining structural changes in a longwall mine, including:

a modulator wheel for frictionally engaging with a rail of a monorail system, the monorail system for supplying services to a longwall mining machine; and

a controller in communication with the modulator wheel;

wherein a distance moved by the longwall mining machine is determined according to a signal received by the controller from the modulator wheel.

In yet another form the invention resides in a method of determining structural changes in a longwall mine including the steps of:

-   -   measuring a signal received from a modulator wheel, the         modulator wheel operatively coupled to a longwall mining         machine; and     -   communicating the signal to a controller;

wherein the controller determines a movement of the longwall mining machine according to the signal.

OBJECT OF THE INVENTION

It is an object, of some embodiments of the present invention, to provide consumers with improvements and advantages over the above described prior art, and/or overcome and alleviate one or more of the above described disadvantages of the prior art, and/or provide a useful commercial choice.

BRIEF DESCRIPTION OF THE DRAWINGS

To assist in understanding the invention and to enable a person skilled in the art to put the invention into practical effect, preferred embodiments of the invention are described below by way of example only with reference to the accompanying drawings, in which:

FIG. 1 is a side view of a gate road of a longwall mine;

FIG. 2 is a side view of a system for determining a structural change in a longwall mine installed on a carriage of a monorail system according to an embodiment of the present invention;

FIG. 3 is a detailed top view of the system for determining a structural change in a longwall mine according to an embodiment of the present invention; and

FIG. 4 is a detailed side view of the system of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

Elements of the invention are illustrated in concise outline form in the drawings, showing only those specific details that are necessary to understanding the embodiments of the present invention, but so as not to clutter the disclosure with excessive detail that will be obvious to those of ordinary skill in the art in light of the present description.

In this patent specification, adjectives such as first and second, left and right, front and back, top and bottom, etc., are used solely to define one element from another element without necessarily requiring a specific relative position or sequence that is described by the adjectives. Words such as “comprises” or “includes” are not used to define an exclusive set of elements or method steps. Rather, such words merely define a minimum set of elements or method steps included in a particular embodiment of the present invention. It will be appreciated that the invention may be implemented in a variety of ways, and that this description is given by way of example only.

FIG. 1 is a cross-sectional side view of a longwall mine. As longwall mining machine 10 cuts material from a rock face (perpendicular to the page), the material falls onto longwall conveyor 12, and is transported to a beam stage loader 20 located in gate road 30. The material passes along the beam stage loader 20 onto a gate road conveyor 40 which transports the material out of the mine as is known in the art.

Services 50 to the longwall mining machine 10, such as power, hydraulics and communications, are supplied along a monorail system 60. The monorail system 60 includes a rail 62 which is attached to a ceiling 32 of the gate road 30. The services 50 are connected to carriages 64, and wheels of each carriage 64 run along the rail 62 and allow the services 50 to concertina as the longwall mining machine 10 retreats towards an entrance 34 of the gate road 30.

FIG. 2 is a side view of a system 70 for determining a structural change in a longwall mine installed on a carriage of the monorail system 60 of FIG. 1 according to an embodiment of the present invention. As shown in FIG. 2, the system 70 is installed on an end carriage 64B which is connected to, and moves in unison with, the beam stage loader 20 and hence the longwall mining machine 10.

FIG. 3 is a top view of the system 70 mounted to the end carriage 64B and FIG. 4 is a side view of the system 70. As shown in FIGS. 3 and 4, the system 70 includes an arm 72, a modulator wheel 74, a controller 76 and a communication channel 78.

The arm 72 is mounted to the end carriage 64B and the modulator wheel 74 is mounted to the arm 72. The modulator wheel 74 frictionally engages with the rail 62, either directly or via a caster wheel attached to a shaft of the modulator wheel 74. The controller 76 is in communication with the modulator wheel 74 via the communication channel 78.

The communication channel 78 may be optical, such as an optical fibre, electrical, such as a metallic cable, wireless or any other suitable means of communication. In the case of a physical communication channel 78, the communication channel 78 may be routed with the services 50 out of the mine to the controller 76.

In some embodiments, the modulator wheel 74 is an optical modulator wheel. Alternatively, the modulator wheel 74 is an electrical modulator wheel or uses a combination of optics and electronics. The advantage of a purely optical modulator wheel is that it does not require a fireproof enclosure, and is less susceptible to interference.

The controller 76 receives a signal from the modulator wheel 74 via the communication channel 78 as the modulator wheel 74 rotates. The controller 76 determines an amount of movement of the modulator wheel 74, and hence the position of the mining machine, according to the signal received from the modulator wheel 74.

In a preferred embodiment, the modulator wheel 74 and the controller 76 are a MR330 Fiber Optic Position Sensor System including a MR332 Sensor and a MR330-1 SSI Controller Module manufactured by Micronor Inc. of Newbury Park, Calif., USA. However it should be appreciated that other optical positioning sensors and controllers may be used.

In one embodiment, the modulator wheel 74 includes a disc (not shown) which rotates as the carriage 64B moves along the rail 62.

In one embodiment, the communication channel 78 is a two core optical fibre, a first core for transmitting light and a second core for receiving light, in this embodiment, the controller 76 may include a light source which is output into the first core of the optical fibre and is directed onto the disc. Light output from the controller 76 may be pulsed. However it should be appreciated that the light source may be continuous. The disc may include a pattern formed from one or more reflective and non-reflective bands. As the modulator wheel 74 and hence the disc rotates, the light from the optical fibre is modulated and received on the second core of the optical fibre.

In one embodiment, the light is modulated by a single reflective and non reflective band. in another embodiment, light is illuminated onto a section of the disc, where each section illuminated includes a unique pattern and the light is modulated according to the unique pattern.

The modulated light is communicated to the controller 76. From the modulated light, the controller 76 determines an amount of movement of the modulator wheel 74 and hence a distance moved by the end carriage 64B and the longwall mining machine 10. A computer (not shown) is connected to the controller 76 to graphically show a user a position of the longwall mining machine 10 within a mine. In one embodiment, the computer connects to the controller 76 via a Local Area Network.

In the case of a single reflective and non-reflective band on the disc, a pulse is output each time the disc turns a single revolution. From the number of pulses, the controller 76 may determine a movement of the wheel.

In the case of light modulated by a unique pattern on the disc, the controller 76 may determine an exact position of the disc from the light modulated according to the unique pattern. In this embodiment, the controller is able to determine whether the modulator wheel 74 is moving clockwise or anti-clockwise thus whether the longwall mining machine 10 is moving backwards or forwards.

In summary, advantages of the present invention are:

-   -   1) The system is lightweight and does not require heavy lifting         equipment to be installed;     -   2) In the case of the optical modulator wheel, it is not         affected by electrical noise and magnetic fields as it utilises         light;     -   3) In the case of the optical modulator wheel, it is a sealed         unit, thus does not require cleaning and works in dusty and         dirty mining environments;     -   4) In the case of an optical modulator wheel it does not need to         be installed in a certified fireproof enclosure and no periodic         testing of the enclosure is required as only optical signals are         used; and     -   5) The system uses a relative movement using a wheel operatively         connected to the mining machine, thus a measurement is more         accurate over the prior art.

The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. Accordingly, this patent specification is intended to embrace all alternatives, modifications and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention. 

1. A system for determining structural changes in a longwall mine, including: a modulator wheel operatively coupled to a longwall mining machine; and a controller in communication with the modulator wheel; wherein the controller determines a movement of the longwall mining machine according to a signal received from the modulator wheel.
 2. The system of claim 1 wherein the modulator wheel is an optical modulator wheel.
 3. The system of claim 1 wherein the modulator wheel is an electrical modulator wheel.
 4. The system of claim 1 wherein the controller is in optical communication with the modulator wheel.
 5. The system of claim 1 wherein the controller is in electrical communication with the modulator wheel.
 6. The system of claim 1 wherein the modulator wheel frictionally engages with a rail of a monorail system supplying services to the longwall mining machine.
 7. The system of claim 1 wherein the modulator wheel is mounted to an arm.
 8. The system of claim 7 wherein the arm is mounted to an end carriage of the monorail system.
 9. The system of claim 1 wherein an optical fibre connects the controller to the modulator wheel.
 10. The system of claim 1 wherein the controller is connected to a local area network.
 11. A method of determining structural changes in a longwall mine including the steps of: measuring a signal received from a modulator wheel, the modulator wheel operatively coupled to a longwall mining machine; and communicating the signal to a controller; wherein the controller determines a movement of the longwall mining machine according to the signal.
 12. The method of claim 11 wherein the modulator wheel is an optical modulator wheel.
 13. The method of claim 11 wherein the modulator wheel is an electrical modulator wheel.
 14. The method of claim 11 wherein the controller is in optical communication with the modulator wheel.
 15. The method of claim 11 wherein the controller is in electrical communication with the modulator wheel.
 16. The method of dam 11 wherein the modulator wheel frictionally engages with a rail of a monorail system supplying services to the longwall mining machine.
 17. The method of claim 11 wherein the modulator wheel is mounted to an arm.
 18. The method of claim 17 wherein the arm is mounted to an end carriage of the monorail system.
 19. The method of dam 11 wherein an optical fibre connects the controller to the modulator wheel.
 20. A system for determining structural changes in a longwall mine, including: a modulator wheel for frictionally engaging with a rail of a monorail system, the monorail system for supplying services to a longwall mining machine; and a controller in communication with the modulator wheel; wherein a distance moved by the longwall mining machine is determined according to a signal received by the controller from the modulator wheel. 